I don't have specific knowledge of handling one of those barrels myself personally, but what I CAN tell you is that for the past couple years my local HB club: "B.A.R.F." (beer and ale research foundation) has been using a 55 gal bourbon barrel to age our club beers. We usually have about 10-15 people brew 5 gal of a specific recipe for it. I got in on it for the first time last year when we brewed an Imperial IPA. It is awesome!! It sat in the barrel for right around a year!!! I currently have it on tap right now! I also just brewed up my 5 gallons of this years bourbon barrel beer: Imperial Brown Ale...they just cleaned/re-filled the barrel about 2 weeks ago. I can't wait to get that Imperial Brown back this time next year!
...and the cycle continues.
All I can say about the flavor is that it definitely continues after numerous uses, ours does. MY BEST suggestion is to try and get in with a bunch of people on a big barrel and it won't cost so much out of pocket...and you can RE-USE it plenty of times! Our HB club just uses it as a group and keeps it up at the LHBS year round!!! SO CONVENIENT!!!
Seasoned Rips Brewery